The increased number of people traveling has caused the growth of transportation services enormously. The airplane is the fastest and most efficient transportation between cities, islands, or even continents. Airlines continue to buy new or used aircraft that are still eligible to meet the increasing demands of passengers each year. Aircraft must have a Certificate of Airworthiness (C of A) to be used for flight. C of A is valid for a year if the airworthiness of the aircraft maintained by routine maintenance and does not experience incidents or accidents. Before C of A expires, an inspection of the aircraft conducted as a condition for extension of the certificate. The aircraft was inspected by a civil aviation inspector from DGCA to determine whether the aircraft was in airworthy condition or not. If it is not feasible, improvements should be carried out to the parts of the examination findings. This research classifies from C of A data inspection using the KNN and Naïve Bayes method to evaluate features that affected the condition of the aircraft. The best accuracy results using KNN method from the selected features obtained 83%. This study has proven to be able to determine the conditions on an aircraft from the feature that already selected.